@protoutil/core

@protoutil/core

A set of utilities for working with protobuf types. These utilities assume you are using protobuf-es to work with messages.

Install

npm install @protoutil/core

Entry Points

The package has four entry points:

Entry Point	Import Path	Contents
Core	@protoutil/core	CheckSum, Fields, integer validators, error classes
Google RPC Types	@protoutil/core/google/rpc	Generated google/rpc exports plus helpers for Code and Status
Well-Known Types	@protoutil/core/wkt	Duration, FieldMask, Timestamp, including Temporal-based parsing and conversion helpers
Google Common Types	@protoutil/core/google/type	Generated google/type exports plus helpers for CalendarPeriod, Color, Date, DateTime, DayOfWeek, Decimal, Fraction, Interval, LatLng, LocalizedText, Month, Money, PhoneNumber, PostalAddress, Quaternion, and TimeOfDay, including Temporal-based conversions

CheckSum

The checksum function calculates a non-cryptographic checksum for a given message. Any two messages with identical values produce identical checksums. Internally, this is used for pagination page tokens and ETags in the @protoutil/aip package.

import { checksum } from "@protoutil/core";

const message1 = create(MySchema, { foo: "bar" });
const checksum1 = checksum(MySchema, message1);

const message2 = create(MySchema, { foo: "bar" });
const checksum2 = checksum(MySchema, message2);

const message3 = create(MySchema, { baz: "quz" });
const checksum3 = checksum(MySchema, message3);

checksum1 === checksum2; // true
checksum1 === checksum3; // false

Fields

The getField and setField functions get and set field values on a message, with support for oneof fields:

import { getField, setField } from "@protoutil/core";

getField(message, fieldDescriptor); // Gets the value (or returns undefined)
setField(message, fieldDescriptor, value); // Sets the value

Both functions check that the field descriptor belongs to the message’s type and throw an error on mismatch. setField does not validate the value’s type before setting.

Duration

A Duration represents a signed, fixed-length span of time represented as a count of seconds and fractions of seconds at nanosecond resolution.

Import from @protoutil/core/wkt:

import {
  duration,
  assertValidDuration,
  isValidDuration,
  durationToString,
  durationFromNanos,
  durationNanos,
  clampDuration,
} from "@protoutil/core/wkt";

Creating Durations

duration(1n, 1_000_000); // 1.001 seconds
duration(315_576_000_001n); // throws — max is +-10,000 years

Validation

assertValidDuration(d); // throws if invalid
isValidDuration(d); // true/false

String Conversion

durationToString(d); // "1.001s"

Nanosecond Conversion

durationFromNanos(1_000_000n); // Duration representing 1 millisecond
durationNanos(d); // BigInt nanoseconds

Clamping

const min = duration(5n);
const max = duration(10n);
clampDuration(duration(15n), min, max); // returns max
clampDuration(duration(1n), min, max); // returns min
clampDuration(duration(7n), min, max); // returns original

Without arguments, clampDuration clamps to the protobuf spec range (-315,576,000,000s to +315,576,000,000s).

Temporal API

import {
  durationFromString,
  durationFromTemporal,
  durationTemporal,
} from "@protoutil/core/wkt";

durationFromString("2s"); // Duration message representing 2 seconds
durationFromTemporal(temporalDuration); // Duration message
durationTemporal(message); // Temporal.Duration

Timestamp

A Timestamp represents a point in time independent of any time zone or local calendar, encoded as a count of seconds and fractions of seconds at nanosecond resolution.

Range is from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z.

Import from @protoutil/core/wkt:

import {
  timestamp,
  assertValidTimestamp,
  isValidTimestamp,
  timestampFromNanos,
  timestampNanos,
  roundTimestampNanos,
  clampTimestamp,
} from "@protoutil/core/wkt";

Creating Timestamps

timestamp(1n, 1_000_000); // 1.001 seconds after unix epoch
timestamp(253402300800n); // throws — max is 9999-12-31T23:59:59.999999999Z

Validation

assertValidTimestamp(ts); // throws if invalid
isValidTimestamp(ts); // true/false

Nanosecond Conversion

timestampFromNanos(1_000_000n); // 1ms after epoch
timestampNanos(ts); // BigInt nanoseconds

Math Example

const epoch = timestampFromNanos(0n);
const oneWeek = duration(7n * 24n * 60n * 60n);
const oneWeekLater = timestampFromNanos(timestampNanos(epoch) + durationNanos(oneWeek));

Rounding

Ensure nanos is an integer after calculations:

let ts = create(TimestampSchema, { nanos: 3 / 2 });
ts = roundTimestampNanos(ts);
assertValidTimestamp(ts); // does not throw

Clamping

clampTimestamp(timestamp(15n), min, max); // clamp to range

Without arguments, clamps to the protobuf spec range (0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z).

Temporal API

import {
  temporalTimestampNow,
  timestampFromInstant,
  timestampFromString,
  timestampInstant,
  timestampToString,
} from "@protoutil/core/wkt";

timestampFromString("1970-01-01T02:07:34.000000321+07:00"); // Timestamp message
timestampToString(ts); // "1970-01-01T00:00:00.000000000Z"
temporalTimestampNow(); // Timestamp with nanosecond resolution
timestampFromInstant(instant); // from Temporal.Instant
timestampInstant(ts); // to Temporal.Instant

Google RPC Types

Import from @protoutil/core/google/rpc:

import {
  BadRequestSchema,
  Code,
  ErrorInfoSchema,
  assertValidCode,
  badRequest,
  badRequestFieldViolation,
  codeFromString,
  codeToString,
  errorInfo,
  isValidCode,
  localizedMessage,
  retryInfo,
  assertValidStatus,
  isValidStatus,
  status,
} from "@protoutil/core/google/rpc";

Code

codeFromString("not_found"); // Code.NOT_FOUND
codeToString(Code.PERMISSION_DENIED); // "PERMISSION_DENIED"

Code helpers validate the protobuf enum values and provide canonical enum-name string conversion.

assertValidCode(value); // throws if invalid
isValidCode(value); // true/false

Error Details

The entry point re-exports the generated standard error detail messages from google/rpc/error_details.proto and adds constructors plus validators for each top-level detail type.

errorInfo("BOOK_NOT_FOUND", "library.example.com", {
  resource: "publishers/1/books/2",
});

badRequest([
  badRequestFieldViolation(
    "name",
    "is required",
    "FIELD_REQUIRED",
    localizedMessage("en-US", "Name is required"),
  ),
]);

retryInfo(duration(3n));

Helpers are available for ErrorInfo, RetryInfo, DebugInfo, QuotaFailure, PreconditionFailure, BadRequest, RequestInfo, ResourceInfo, Help, LocalizedMessage, and their nested violation/link messages.

Creating Status Values

status(Code.NOT_FOUND, "Book not found");

status() creates a validated google.rpc.Status. code must be one of the canonical google.rpc.Code enum values, message is the developer-facing error text, and details may contain packed google.protobuf.Any values.

Validation

assertValidStatus(value); // throws if invalid
isValidStatus(value); // true/false

Validation checks that code is a defined google.rpc.Code enum value, message is a string, and details contains only google.protobuf.Any messages.

Google Common Types

Import from @protoutil/core/google/type:

import {
  CURRENCY_CODES,
  CalendarPeriod,
  CalendarPeriodSchema,
  ColorSchema,
  DateSchema,
  DateTimeSchema,
  DayOfWeek,
  DayOfWeekSchema,
  DecimalSchema,
  FractionSchema,
  IntervalSchema,
  LatLngSchema,
  LocalizedTextSchema,
  Month,
  MonthSchema,
  MoneySchema,
  PhoneNumberSchema,
  PostalAddressSchema,
  QuaternionSchema,
  TimeZoneSchema,
  TimeOfDaySchema,
  type CurrencyCode,
  assertValidLanguageCode,
  assertValidRegionCode,
  calendarPeriodFromString,
  calendarPeriodToString,
  color,
  date,
  dateFromString,
  dateToString,
  dateTime,
  dateTimeFromString,
  dateTimeToString,
  dayOfWeekFromString,
  dayOfWeekToString,
  decimal,
  decimalFromString,
  decimalToString,
  fraction,
  fractionFromString,
  fractionToString,
  interval,
  latLng,
  isValidLanguageCode,
  isValidRegionCode,
  localizedText,
  monthFromString,
  monthToString,
  isCurrencyCode,
  money,
  moneyFromDecimal,
  moneyToDecimal,
  phoneNumber,
  phoneNumberShortCode,
  postalAddress,
  quaternion,
  timeZone,
  timeOfDay,
  timeOfDayFromString,
  timeOfDayToString,
} from "@protoutil/core/google/type";

The entry point re-exports the generated google/type messages and adds convenience helpers for the most common API-facing types, including Temporal-based conversions:

import {
  dateFromPlainDate,
  datePlainDate,
  dateTimeFromPlainDateTime,
  dateTimeFromZonedDateTime,
  dateTimePlainDateTime,
  dateTimeZonedDateTime,
  intervalFromInstants,
  intervalInstants,
  timeOfDayFromPlainTime,
  timeOfDayPlainTime,
} from "@protoutil/core/google/type";

CalendarPeriod

calendarPeriodFromString("week");
calendarPeriodToString(CalendarPeriod.FORTNIGHT); // "FORTNIGHT"

CalendarPeriod helpers validate the protobuf enum values CALENDAR_PERIOD_UNSPECIFIED through YEAR and provide canonical enum-name string conversion. WEEK and FORTNIGHT follow ISO 8601 week boundaries, and all calendar periods begin at midnight UTC.

Color

color(1, 0, 0); // solid red
color(0.25, 0.5, 0.75, 0.4);

Color helpers validate RGBA channels in the protobuf interval [0, 1]. alpha is optional; when omitted, the color should be rendered as solid, as if alpha were 1.0.

Date

date(2024, 3, 2); // full date
date(2024, 0, 0); // year-only
date(2024, 3, 0); // year-month
date(0, 2, 29); // month-day anniversary

dateFromString("--02-29");
dateToString(date(2024, 3, 2)); // "2024-03-02"

Date helpers support all four protobuf date shapes: full dates, year-only values, year-month values, and month-day values. A yearless date must include both month and day.

Temporal conversions for full dates are available from @protoutil/core/google/type.

Decimal

decimal("12.34");
decimalFromString(".5");
decimalToString(decimal("1E+05")); // "1e5"

Decimal helpers validate the protobuf decimal grammar and normalize helper-created values to a canonical string form. Normalization removes a leading +, inserts a leading 0 for fractional-only values, lowercases exponents, and drops zero exponents.

They also preserve precision rather than rounding: this package does not currently impose a maximum decimal precision or scale. Trailing fractional zeroes are preserved, but equivalent values are not otherwise rewritten across exponent and decimal notation, so 2.5e-1 stays 2.5e-1 instead of being reformatted as 0.25. Locale-specific separators like , are rejected.

DateTime

dateTime({
  year: 2024,
  month: 3,
  day: 2,
  hours: 8,
  minutes: 48,
  timeZone: "America/New_York",
});

dateTimeFromString("2024-03-02T08:48:00-05:00");
dateTimeToString(dateTimeFromString("2024-03-02T08:48:00[America/New_York]"));

DateTime helpers support local datetimes, UTC offsets, and IANA Time Zone Database zones.

They intentionally use a strict v1 subset of the protobuf type: hours must be 00 through 23, seconds must be 00 through 59, and utcOffset must be whole seconds within ±18:00. Yearless datetimes are supported, but Temporal conversions back to Temporal.PlainDateTime or Temporal.ZonedDateTime require a non-zero year.

When you use timeZone, the helpers rely on Temporal’s default "compatible" disambiguation for IANA zones. In practice, ambiguous fall-back times prefer the earlier offset, and skipped spring-forward times keep the requested civil fields while resolving with the post-transition offset. The named-zone validation is shared with timeZone(), and DateTime adds the extra requirement that the specific civil time must resolve in that zone. If you need an exact offset with no timezone database lookup, use utcOffset instead.

DayOfWeek

dayOfWeekFromString("wednesday");
dayOfWeekToString(DayOfWeek.SUNDAY); // "SUNDAY"

DayOfWeek helpers validate the protobuf enum values DAY_OF_WEEK_UNSPECIFIED through SUNDAY and provide canonical enum-name string conversion.

Fraction

fraction(1n, 2n);
fractionFromString("3"); // 3/1
fractionFromString("2/3");
fractionToString(fraction(3n, 4n)); // "3/4"

Fraction helpers validate the protobuf contract directly: numerator is any int64 and denominator must be positive. fractionFromString() accepts canonical numerator/denominator strings and whole-number shorthand like "3" for 3/1. fractionToString() always formats canonically as numerator/denominator, so valid fractions like 2/3 and 3/1 round-trip without special cases.

Interval

interval();

Interval helpers model the protobuf contract directly: startTime is inclusive, endTime is exclusive, and startTime must be less than or equal to endTime. Equal bounds represent an empty interval, and omitting both bounds represents an interval that matches any time.

Temporal conversions to and from Temporal.Instant are available from @protoutil/core/google/type.

LatLng

latLng(37.422, -122.084);
latLng(-90, -180);
latLng(90, 180);

LatLng helpers validate the protobuf contract directly: unless specified otherwise, coordinates must conform to the WGS84 standard, and values must already be normalized. Latitude must be in [-90, 90] and longitude must be in [-180, 180].

LocalizedText

localizedText("Hello", "en-US");
localizedText("Zdravo", "sr-Latn");

LocalizedText helpers validate the protobuf contract directly: text is the localized string, and languageCode must be a valid BCP 47 language tag such as "en-US" or "sr-Latn". For locale identifier details, see the Unicode locale identifier reference. Shared isValidLanguageCode() and assertValidLanguageCode() helpers are also exported for code that needs to validate the same language tags outside LocalizedText.

Month

monthFromString("march");
monthToString(Month.SEPTEMBER); // "SEPTEMBER"

Month helpers validate the protobuf enum values MONTH_UNSPECIFIED through DECEMBER and provide canonical enum-name string conversion.

Money

money("USD", 12n, 340_000_000); // 12.34 USD
moneyFromDecimal("USD", "12.34");
moneyToDecimal(money("USD", -1n, -750_000_000)); // "-1.75"

money() and moneyFromDecimal() accept CurrencyCode rather than a raw string. The union and CURRENCY_CODES list are generated from Intl.supportedValuesOf("currency") using ISO 4217 currency codes and can be refreshed with: moneyFromDecimal() accepts strings, whole-number bigints, and finite non-scientific numbers. Money values support at most 9 fractional digits, and units/nanos must use compatible signs.

pnpm --dir packages/core run update:currencies

PhoneNumber

phoneNumber({ e164Number: "+15552220123" });
phoneNumber({ e164Number: "+15552220123", extension: "123,#" });
phoneNumber({ shortCode: { regionCode: "US", number: "611" } });
phoneNumberShortCode("BB", "211");

PhoneNumber helpers validate the protobuf wire contract directly: each value must include either a relaxed ITU E.164 number or a short code. E.164 numbers must start with + and contain digits only, with no spaces or locale-specific formatting such as "+1 (650) 253-0000 ext. 123". National-only numbers are not allowed.

Short codes must include both a valid Unicode region subtag such as "US" or "BB" and digits-only short-code number text with no leading + or country calling code. extension is optional and may include dialing characters such as , and #, but may not contain more than 40 digits. Shared isValidRegionCode() and assertValidRegionCode() helpers are also exported for callers that need the same region validation directly.

PostalAddress

postalAddress({
  regionCode: "US",
  addressLines: ["1600 Amphitheatre Parkway"],
  locality: "Mountain View",
  administrativeArea: "CA",
  postalCode: "94043",
});

PostalAddress helpers validate the protobuf wire contract directly: revision must be 0, regionCode is required and must be a valid CLDR / Unicode region code such as "US" or "CH", and languageCode, when present, must be a valid BCP 47 language tag.

Region validation uses an explicit Unicode CLDR region-code table, generated from the CLDR JSON territoryContainment.json dataset, rather than relying only on syntactic shape checks.

The helper does not impose country-specific postal rules beyond what the proto docs require. The protobuf docs explicitly allow minimally structured addresses that use regionCode plus unstructured addressLines, so this helper accepts that pattern without trying to infer locality or administrative fields.

Quaternion

quaternion(0, 0, 0, 1);
quaternion(0.5, -0.5, 0.5, -0.5);
quaternion(2, 0, 0, 0);

Quaternion helpers follow the protobuf wire contract directly: x, y, z, and w must be finite real-number components. The protobuf docs describe Hamilton-convention quaternion semantics and recommend normalization practices for rotations, but this helper does not normalize values, enforce unit length, or require positive w. Those choices are left to callers and service-level policy.

TimeZone

timeZone("UTC");
timeZone("America/New_York", "2024a");

TimeZone helpers validate the protobuf wire contract directly: id must be a non-empty recognized IANA Time Zone Database zone ID such as "America/New_York" or "UTC". version is preserved as optional metadata and is not interpreted or validated by this helper.

TimeOfDay

timeOfDay(8, 48, 1, 234_000_000);
timeOfDayFromString("08:48:01.234");
timeOfDayToString(timeOfDay(23, 59, 59, 999_999_999)); // "23:59:59.999999999"

TimeOfDay helpers are intentionally strict in v1: they accept 00:00:00 through 23:59:59.999999999, but do not currently allow 24:00:00 or leap-second :60 values.

Temporal conversions for TimeOfDay are available from @protoutil/core/google/type.

FieldMask

FieldMask represents a set of symbolic field paths used to specify a subset of fields that should be returned by a get operation or modified by an update operation.

Import from @protoutil/core/wkt:

import {
  fieldMask,
  assertValidFieldMask,
  isValidFieldMask,
  fieldMaskHasPath,
  applyFieldMask,
  mergeFieldMasks,
  intersectFieldMasks,
} from "@protoutil/core/wkt";

Strict vs Non-Strict Mode

All FieldMask functions accept a strict parameter (default: true). In strict mode, only spec-compliant field masks are allowed. Set strict to false to allow wildcards (*) per the AIP Guidelines.

Creating FieldMasks

fieldMask(MySchema, ["my_path", "my_other_path"]);
// throws if fields don't exist on MySchema

Validation

assertValidFieldMask(MySchema, fm); // throws if invalid
isValidFieldMask(MySchema, fm); // true/false

Path Matching

const fm = fieldMask(MySchema, ["a"]);
fieldMaskHasPath(fm, "a"); // true
fieldMaskHasPath(fm, "b"); // false
fieldMaskHasPath(fm, "a.b"); // true — "a" covers nested fields

Applying

const fm = fieldMask(MySchema, ["a"]);
applyFieldMask(MySchema, message, fm); // only "a" field populated
applyFieldMask(MySchema, message, fm, { inverse: true }); // everything EXCEPT "a"

applyFieldMask does not mutate the original message. Options:

Option	Default	Description
inverse	false	When true, applies the inverse of the mask
strict	true	When false, allows wildcards in the mask

Merging

Combines paths — parent fields subsume their children:

const one = fieldMask(MySchema, ["a"]);
const two = fieldMask(MySchema, ["a.b", "c"]);
mergeFieldMasks(one, two); // paths: ["a", "c"]

Intersecting

Returns only paths present in all masks — child paths preferred over parents:

intersectFieldMasks(one, two); // paths: ["a.b"]

Integer Validators

Import from @protoutil/core:

Function	Description
assertValidInt32(num)	Throws if num is not a 32-bit signed integer
isValidInt32(num)	Returns true if num is a 32-bit signed integer
assertValidInt64(num)	Throws if num (BigInt) is not a 64-bit signed integer
isValidInt64(num)	Returns true if num (BigInt) is a 64-bit signed integer
assertValidUInt32(num)	Throws if num is not a 32-bit unsigned integer
isValidUInt32(num)	Returns true if num is a 32-bit unsigned integer
assertValidUInt64(num)	Throws if num (BigInt) is not a 64-bit unsigned integer
isValidUInt64(num)	Returns true if num (BigInt) is a 64-bit unsigned integer

Error Classes

Import from @protoutil/core:

Class	Description
OutOfRangeError	Indicates a value is out of range. Properties: value, min, max.
InvalidValueError	Indicates a value is invalid. Properties: value.

Unit Testing Schemas

This library exports the Google protobuf unit testing schemas compiled from the protocolbuffers repository. These are useful when testing protobuf-dependent libraries.

// Main test types (proto2)
import { TestAllTypesSchema } from "@protoutil/core/unittest";

// Proto3-specific types
import { TestAllTypes_NestedEnumSchema } from "@protoutil/core/unittest/proto3";

Many additional schemas are available under @protoutil/core/unittest/* sub-paths (arena, custom-options, features, lite, etc.). Please explore the repository or file an issue if you need a schema that isn’t exported.

API Reference

@protoutil/core

Export	Description
checksum(schema, message)	Calculate a non-cryptographic checksum for a message
getField(message, field)	Get a field value from a message (supports oneof)
setField(message, field, value)	Set a field value on a message (supports oneof)
assertValidInt32(num) / isValidInt32(num)	Validate 32-bit signed integers
assertValidInt64(num) / isValidInt64(num)	Validate 64-bit signed integers
assertValidUInt32(num) / isValidUInt32(num)	Validate 32-bit unsigned integers
assertValidUInt64(num) / isValidUInt64(num)	Validate 64-bit unsigned integers
OutOfRangeError	Error for out-of-range values
InvalidValueError	Error for invalid values

@protoutil/core/wkt

Export	Description
duration(seconds, nanos?)	Create a validated Duration
assertValidDuration(d) / isValidDuration(d)	Validate a Duration
durationToString(d)	Convert Duration to string
durationFromNanos(n) / durationNanos(d)	Convert Duration to/from nanoseconds
clampDuration(d, min?, max?)	Clamp a Duration to a range
timestamp(seconds, nanos?)	Create a validated Timestamp
assertValidTimestamp(ts) / isValidTimestamp(ts)	Validate a Timestamp
timestampFromNanos(n) / timestampNanos(ts)	Convert Timestamp to/from nanoseconds
roundTimestampNanos(ts)	Round Timestamp nanos to an integer
clampTimestamp(ts, min?, max?)	Clamp a Timestamp to a range
fieldMask(schema, paths, strict?)	Create a validated FieldMask
assertValidFieldMask(schema, fm, strict?) / isValidFieldMask(schema, fm, strict?)	Validate a FieldMask
fieldMaskHasPath(fm, path, strict?)	Check if a FieldMask matches a path
applyFieldMask(schema, message, fm, opts?)	Apply a FieldMask to a message. Options: { inverse?, strict? }
mergeFieldMasks(...masks)	Merge multiple FieldMasks
intersectFieldMasks(...masks)	Intersect multiple FieldMasks

Classes

• InvalidValueError
• OutOfRangeError

Variables

• MAX_INT32
• MAX_INT64
• MAX_UINT32
• MAX_UINT64
• MIN_INT32
• MIN_INT64

Functions

• assertValidInt32
• assertValidInt64
• assertValidUInt32
• assertValidUInt64
• checksum
• getField
• isValidInt32
• isValidInt64
• isValidUInt32
• isValidUInt64
• setField